We plan to continue the investigation of the catecholamine metabolism of neuroblastomas and other tumors which synthesize catecholamines. We plan to extend our studies of the enzyme tyrosine hydroxylase, which have already been extensively made on pheochromocytomas, to neuroblastomas and ganglioneuromas, including studies of the effects of inhibitors and characterization of the enzyme. We also plan to study the enzyme dopamine B-hydroxylase including determination of activity in plasma of patients with pheochromocytomas, neuroblastomas and ganglioneuromas. We plan to characterize the enzyme after purification from tumor tissue. We intend to continue our study of these tumors in tissue culture, studying catecholamine synthesis and degradation and cell differentiation. We plan to study catecholamine/ATP molar ratios in chromaffin granules in neuroblastomas. Clinical studies of patients will be continued. Studies of cellular and humoral immunity against neuroblastomas will be extended to pheochromocytomas and ganglioneuromas. It is hoped that increased understanding of the catecholamine metabolism of these tumors will lead to improved methods of diagnosis and treatment.